Questionnaire Validation Made Easy - EuroJournals

176 Suri Sushil and Verma N
Difference between test/retest and Internal Consistency
The primary difference between test/retest and internal consistency estimates of reliability is that
test/retest involves two administrations of the measurement instrument, whereas the internal
consistency method involves only one administration of that instrument. (9)
Bias
“Bias often occurs due to distortions in procedures and characteristics of instruments, observers, and
investigators. While bias can occur due to intentional acts on the part of researchers, of particular
concern here is bias that is unintentional, arising from instruments. Bias is far more problematic than
random error, most often investigators attempt to uncover its sources and design instruments or
methods to avoid it and in fact much effort in designing studies involves the avoidance of bias.”(8)
Validated Questionnaire
“A validated questionnaire is one which has undergone a validation procedure to show that it
accurately measures what it aims to do, regardless of who responds, when they respond, and to whom
they respond or when self administered.The instrument is compared against the available “Gold
standard”. It is compared with other sources of data. The reliability is also examined.Even if a
questionnaire is not completely valid (which it hardly ever will be) the reliability of the instrument has
a value of its own. If an instrument is reliable this offers the opportunity to compare results from one
study with work that has been done by others. This is of special value if measurements are taken at
different points in time or in the different regions.”(3)
Standard Questionnaire
A questionnaire ,to serve a purpose, when examined and approved by committee or working group of
scholars from numerous disciplines, acceptable to the broader scientific community is known as the
standard questionnaire.(3)
Discussion and Conclusions
“Research studies include qualitative approaches (11) or the use of questionnaires (12,13). The
validation of questionnaire has important implications for research methodology and the validity of the
research outcomes and thus important for clinicians/epidemiologists who wish to use questionnaires as
a research tool. Research outcome is directly dependant upon the quality and the completeness of the
data used. ‘Indeed when it comes to questionnaire development, the concerns of willingness to
respond, discriminatory power, comparability, responsiveness/reliability and validity of data seem
sometimes to be forgotten. This problem appears to be inherent to many areas of medical science,
whenever questionnaires are concerned; the valuable body of knowledge and experience of other
disciplines, especially the cognitive and social sciences, is often ignored” (17) Even though many
questionnaires deal with the same information and aim to answer the same questions, there are not any
ordered or standardized collections where researcher can view questionnaires of the same genre
together. If the similar questionnaires are collected together, then researchers would find it easy and
less time consuming to find information for their research. This is will increase efficiency and
productivity. Another important point that needs to be taken into consideration is the quality of these
questionnaires, thus more thought should be spent while framing these questions so that researcher can
have an accurate sample and the research is more authentic.
Sometimes researchers introduce their own instruments to enhance the questionnaire used in
some previous studies. But this may lead to incompatibility which corrupts the information/data
gathered from the survey. Note that without reliability, there can be no validity. An electronic
thermometer is a valid way to measure temperature, but if it has bad batteries than it gives erratic